To enable the efficient elimination or controlling of unwanted pests and plants, it is desirable to use effective chemical formulations of pesticides. Compositions containing multiple pesticides are desirable in agricultural, specialty and related endeavors due to broadening the spectrum or range of unwanted pest and plant species killed or controlled.
Due to the desirability of having a composition with the above mentioned properties, it is useful to use combinations of pesticides or combinations of a herbicide with another herbicide, insecticide, fungicide etc., to obtain enhanced control of the numerous weeds and pests with a single application. Combinations of pesticides, formulation methods and commercial products of certain combinations of herbicides are known and available. Such combinations are known and available as mixed solutions of the active ingredients in emulsifiable concentrate (EC) formulations, but frequently more complex formulations are required to combine active ingredients with widely different physical properties in order to avoid chemical and physical stability problems.
Clomazone, the common name for 2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone, a highly effective herbicide, is also highly volatile. Clomazone applied to the soil in a target area may move to adjacent areas causing whitening or bleaching of plants near treated fields. Microencapsulated clomazone is used in order to reduce volatility by 50% or less, thereby reducing off-site plant injury, while maintaining a satisfactory level of herbicidal activity in the target area. Although microencapsulated formulations of water-insoluble pesticides control the volatility of pesticides, for example Command 3ME, which is the commercially available microencapsulated formulation of clomazone (FMC Corporation), it has been found that when admixed with a second active substance, external to the microcapsules, the mixture is not stable. It can be shown that if the external substance is oleophilic, attracting water-insoluble substances, then the contents of the microcapsule may be rapidly extracted from the capsules and into the oily disperse phase. Attempts to prepare stable liquid combinations of water-insoluble pesticide microcapsules, such as clomazone, with other active ingredients in the same package have been unsuccessful, either because the volatility of the pesticide is affected by the movement from inside the microcapsule to the oily disperse phase or the composition is not stable.